Development of Cd8α/α and Cd8α/β T Cells in Major Histocompatibility Complex Class I–Deficient Mice

Peripheral CD8+ T cells mainly use CD8α/β, and their development is mainly dependent on the major histocompatibility complex (MHC) class I proteins Kb and Db in H-2b mice. In this report, we have shown that the development of CD8α/β TCR-α/β cells in lymphoid organs as well as in intestinal intraepithelial lymphocytes (iIELs) is dependent on the MHC class I Kb and Db proteins. In contrast, TCR-α/β CD8α/α cells are found mainly in iIELs, and their numbers are unaffected in KbDb double knockout mice. Most of the TCR-γ/δ cells in the iIELs also bear CD8α/α, and they are also unaffected in KbDb −/− mice. In β2-microglobulin (β2m)-deficient mice, all of the TCR-α/β CD8α/α and CD8α/β T cells disappear, but TCR-γ/δ cells are unaffected by the absence of β2m

Immunological tolerance: Danger – pathogen on the premises!

AbstractRecent results show that immune responses can be induced in neonatal mice. Do they really refute the traditional view that the ability to discriminate between ‘self’ and ‘non-self’ is a fundamental property of the immune system

Cross-Antagonism of a T Cell Clone Expressing Two Distinct T Cell Receptors

AbstractInhibition of T cell activation can be mediated by analogs of the original antigenic peptide (TCR antagonists). Here, a T cell clone expressing two distinct TCR was used to investigate whether such inhibition involves an active mechanism by examining whether an antagonist for one TCR could influence responses stimulated by the other TCR engaging its agonist. Our results demonstrate functional cross-inhibition under these conditions involving the ability of antagonist:TCR interactions to diminish Lck enzymatic activity associated with the agonist-recognizing second TCR, apparently through enhancement of SHP-1 association with these receptors. Our findings reveal that inhibition of cellular responses by antagonists arises at least in part from active negative regulation of proximal TCR signaling and identify elements of the biochemical process